Foldable Structural Member, Manufacturing Method Thereof, and Foldable Electronic Device

This application is a continuation of International Application No. PCT/CN2024/079076, filed on Feb. 28, 2024, which claims priority to Chinese Patent Application No. 202310851721.2, filed on Jul. 11, 2023, both of which are incorporated herein by reference in their entireties.

This application relates to the field of electronic technologies, and in particular, to a foldable structural member, a manufacturing method thereof, and a foldable electronic device.

With rapid development of electronic technologies, consumers increasingly pursue lightness and thinness of electronic devices such as mobile phones. Generally, a manufacturer chooses to assemble a magnesium alloy middle frame in an electronic device, so as to improve the lightness and thinness of the electronic device. However, for a currently popular foldable electronic device with a higher requirement for the lightness and thinness, a middle frame thereof generally includes a first middle frame and a second middle frame that are connected to a rotating mechanism. In this case, a rotating open region (including a region into which salt spray and water vapor can infiltrate) necessarily exists in the middle frame. If a full-magnesium alloy middle frame is still adopted, a conventional magnesium alloy anti-corrosion design fails to meet the requirement. In a salt spray environment, galvanic corrosion may occur in the rotating open region, resulting in blockage and failure of the rotating mechanism.

If an anti-corrosion solution, for a bar phone, of packaging the whole magnesium alloy middle frame with full adhesive in coordination with glue dispensing sealing is simply applied to the foldable structural member, the galvanic corrosion at the joint where the magnesium alloy in the rotating open region laps over a steel rotating shaft cannot be solved, resulting in a problem that the whole machine cannot pass a salt spray test. Therefore, product requirements cannot be met. Thus, it is urgently necessary to provide a foldable structural member with a brand-new anti-corrosion design, so as to implement feasibility of using the full-magnesium alloy middle frame in the foldable electronic device.

In view of this, embodiments of this application provide a foldable structural member, a manufacturing method thereof, and a foldable electronic device. The foldable structural member has a special anti-corrosion design, which provides feasibility for a magnesium alloy to be used as a metal body in a rotating open region of the foldable structural member.

A first aspect of the embodiments of this application provides a foldable structural member, including a rotating mechanism, and a first middle frame and a second middle frame that are rotatably connected to the rotating mechanism.

The first middle frame includes a first backplane, the first backplane having a first surface. The second middle frame includes a second backplane, the second backplane having a second surface, and the rotating mechanism lapping over the first surface and the second surface.

A first region and a second region are defined, the first region including a side border that is of the first surface and that is close to the rotating mechanism, and the second region including a side border that is of the second surface and that is close to the rotating mechanism.

The first backplane and the second backplane each include a metal body, a first protective layer disposed on a surface of the metal body, an injection molding layer disposed on at least a surface of the first protective layer in the first region and the second region, and an anti-corrosion layer disposed between the injection molding layer and the first protective layer.

The metal body provides structural strength for the first middle frame and the second middle frame, and plays a specific protective role. When the metal body is applied to the electronic device, the metal body may further serve to assist a processor of the electronic device to radiate heat. The first protective layer may protect the metal body, so as to prevent the metal body from being corroded. In particular, the injection molding layer in the first region and the second region may have a better sealing effect, that is, a risk of salt spray or water vapor infiltrating into the structural member is greatly reduced. Therefore, when a material of the metal body is a magnesium alloy, a risk of galvanic corrosion of the magnesium alloy body in the rotating open region can be sufficiently reduced. However, the anti-corrosion layer may significantly increase an interface bonding force between the first protective layer and the injection molding layer, and avoid a case that the injection molding layer and the first protective layer are poorly bonded and layered, thereby significantly reducing the risk of galvanic corrosion of the metal body, and then providing feasibility for applying a magnesium alloy middle frame (including the first middle frame and the second middle frame) to the foldable electronic device.

In some implementations of this application, the first backplane has a third surface opposite to the first surface and a fourth surface that connects the first surface to the third surface, the fourth surface including the anti-corrosion layer and the injection molding layer that are successively stacked on a surface that is of the first protective layer and that faces away from the metal body.

In some implementations of this application, the second backplane has a fifth surface opposite to the second surface, and a sixth surface that connects the second surface to the fifth surface, the sixth surface including the anti-corrosion layer and the injection molding layer that are successively stacked on a surface that is of the first protective layer and that faces away from the metal body.

In some implementations of this application, the first middle frame and the second middle frame further include a first side frame fastened to the first backplane and a second side frame fastened to the second backplane, respectively. The first side frame, the first backplane, the second backplane, and the second side frame constitute a first accommodating space. The first side frame and the second side frame are manufactured by injection molding. In this way, not only an anti-corrosion effect of the foldable structural member can be fully ensured, but also a limiting effect is implemented on a display in the final electronic device. In addition, an appearance surface of the final electronic device can be further constituted.

In some implementations of this application, the first side frame is integrally molded with the injection molding layer, and the second side frame is integrally molded with the injection molding layer. In this way, strength of the first middle frame and the second middle frame is improved, and manufacturing is also easy.

In some implementations of this application, a thickness of the first protective layer is within a range of 15 μm to 40 μm. In this way, an anti-corrosion effect of the first protective layer can be improved, and a risk of galvanic corrosion of the metal body is further reduced.

In some implementations of this application, the first protective layer is a porous structure, and the first protective layer has a porosity of less than or equal to 15% and an aperture of less than or equal to 20 μm. In this case, the first protective layer has a specific density, itself may implement a better anti-corrosion effect, and further may significantly increase a direct interface bonding force between the first protective layer and the anti-corrosion layer, thereby improving an integral anti-corrosion capability of the first middle frame and the second middle frame.

In some implementations of this application, the first protective layer is a ceramic layer formed by micro-arc oxidation. The ceramic layer manufactured by the micro-arc oxidation has high hardness, strong corrosion resistance and good insulation performance.

In some implementations of this application, a thickness of the injection molding layer is within a range of 0.15 mm to 0.35 mm. In this way, better sealing performance may be achieved, thereby improving a complete-machine anti-corrosion effect of the electronic device, and it can help ensure that the final electronic device is relatively light and thin.

In some implementations of this application, the injection molding layer is an inorganic material reinforced resin layer. Inorganic material reinforced resin has good mechanical performance, and has a good bonding force with a material of the first protective layer.

In some implementations of this application, the anti-corrosion layer is a resin layer. A material of the resin layer includes a cured product of an epoxy resin, a polyester resin and a silane coupling agent. A thickness of the anti-corrosion layer is within a range of 10 μm to 40 μm. In this way, the anti-corrosion layer can implement better corrosion resistance while taking into account the lightness and thinness of the final electronic device.

In some implementations of this application, the anti-corrosion layer includes a first resin layer and a second resin layer that are stacked, and the first resin layer is in contact with the first protective layer. The first resin layer includes a resin distributed with a first-type inorganic filler, the resin including a material prepared from an epoxy resin, a polyester resin, and a silane coupling agent, and the first-type inorganic filler including at least one of hydrophobic silicon dioxide, talc powder, and magnesium powder. The second resin layer includes a cured product of a first-type acrylic resin distributed with a second-type inorganic filler and an isocyanate, the second-type inorganic filler including at least one of silicon dioxide, barium sulfate, and titanium dioxide. In this way, corrosion resistance of the anti-corrosion layer can be further improved.

In some implementations of this application, a thickness of the first resin layer is within a range of 2 μm to 10 μm, and a thickness of the second resin layer is within a range of 10 μm to 30 μm. In this way, the anti-corrosion layer may implement better corrosion resistance.

In some implementations of this application, a transition layer is further disposed between the first resin layer and the second resin layer, the transition layer including a second-type hydroxyacrylic resin. The thickness of the first resin layer is within a range of 2 μm to 10 μm. The thickness of the second resin layer is within a range of 2 μm to 10 μm. A thickness of the transition layer is within a range of 10 μm to 20 μm. In this way, the anti-corrosion layer can implement better corrosion resistance while taking into account the lightness and thinness of the final electronic device.

In some implementations of this application, on the first surface, a second protective layer is further disposed in at least a part of a region that is on a surface on which the anti-corrosion layer is not covered by the injection molding layer and that is adjacent to the injection molding layer. In this way, a galvanic corrosion resistance effect of the rotating open region can be further improved.

In some implementations of this application, on the second surface, a second protective layer is further disposed in at least a part of a region that is on a surface on which the anti-corrosion layer is not covered by the injection molding layer and that is adjacent to the injection molding layer. In this way, the galvanic corrosion resistance effect of the rotating open region can be further improved.

In some implementations of this application, the second protective layer is connected to the injection molding layer.

In some implementations of this application, the second protective layer further covers a surface that is of the injection molding layer and that faces away from the anti-corrosion layer.

In some implementations of this application, the second protective layer includes a fluorine-containing resin, or the second protective layer includes a cured product of a third-type hydroxyacrylic resin and an isocyanate. The fluorine-containing resin also has specific hydrophobicity, and the cured product of a third-type hydroxyacrylic resin and an isocyanate has better compactness.

In some implementations of this application, a thickness of the second protective layer is within a range of 5 μm to 30 μm. In this way, the corrosion resistance and the lightness and thinness of the final electronic device can be considered.

In some implementations of this application, screw holes are disposed in the first region and the second region, the screw holes are adapted to screws, and the screws are configured to fasten the rotating mechanism.

In some implementations of this application, a material of the metal body is a magnesium alloy. In this way, a weight and a thickness of the foldable structural member can be significantly reduced while mechanical performance of the foldable structural member is ensured. When the foldable structural member is applied to the electronic device, market competitiveness of the electronic device can be greatly improved.

providing a metal body, and forming the first protective layer on a surface of the metal body; forming the anti-corrosion layer on at least a surface of the first protective layer in the first region and the second region; and forming the injection molding layer on at least a surface of the anti-corrosion layer in the first region and the second region to manufacture the foldable structural member. A second aspect of this application provides a manufacturing method of the foldable structural member, including:

The manufacturing method has simple steps and high production efficiency, and is applicable to large-scale industrial production.

soaking the metal body in an electrolyte in an electrolytic cell, using the metal body as an anode, using the electrolytic cell as a cathode, applying an electric field, and performing micro-arc oxidation on the metal body at a current density greater than 2 A and less than or equal to 5 A; where the electrolyte includes a solvent, a salt, and a nano additive; and the salt includes at least one of silicate, phosphate, and aluminate. In this way, a first protective layer with a thickness of 15 μm to 40 μm can be manufactured. In some implementations of this application, a process of forming the first protective layer on a surface of the metal body includes:

A third aspect of the embodiments of this application provides a foldable electronic device. The foldable electronic device includes the foldable structural member provided in the first aspect of the embodiments of this application.

In some implementations of this application, the foldable electronic device includes but is not limited to a wearable electronic device such as a mobile phone, a notebook computer, a tablet computer, and an electronic watch.

In some implementations of this application, the foldable electronic device includes a first display and a second display.

The first display is disposed on a first surface of the first middle frame and a second surface of the second middle frame. The first display is a flexible display.

The second display is disposed on a surface that is of the first middle frame and that faces away from the first display, or the second display is disposed on a surface that is of the second middle frame and that faces away from the first display.

100 10 11 111 112 113 114 12 20 21 211 212 213 22 30 40 50 60 70 80 : foldable structural member;: first middle frame;: first backplane;: first surface;: third surface;: first region;: fourth surface;: first side frame;: second middle frame;: second backplane;: second surface;: fifth surface;: second region;: second side frame;: rotating mechanism;: metal body;: first protective layer;: anti-corrosion layer;: injection molding layer; and: second protective layer.

At a current stage, in a mainstream foldable electronic device, two displays may be disposed at the same time, and one of the displays is a flexible screen and may correspondingly change with folding and unfolding of the electronic device. To achieve the foregoing objective, a middle frame of the electronic device needs to be disposed as a foldable structural member, and generally includes a first middle frame and a second middle frame that are connected by using a steel rotating mechanism. A first middle frame and a second middle frame are rotated around the rotating mechanism to implement folding and unfolding of the flexible display. Therefore, the flexible display needs to be attached to both a surface of the first middle frame and a surface of the second middle frame, so that the foldable electronic device cannot implement sealing between the middle frame and the screen in a screen glue dispensing manner like a bar phone (salt spray and water vapor corrosion resistance performance can be implemented). Therefore, the middle frame of the foldable electronic device necessarily has a rotating open region, which means that salt spray or water vapor may enter the region, thereby forming an electrolyte environment in the rotating open region.

In addition, a standard electrode potential (−2.37 V) of a magnesium alloy and the steel rotating mechanism (a potential of steel depends on a standard electrode potential of a main element Fe, about −0.44 V) are greatly different. In the electrolyte environment, the middle frame of the magnesium alloy and the steel rotating mechanism form an original battery circuit, and galvanic corrosion occurs. As an anode, the magnesium alloy loses electrons, resulting in corrosion perforation and local material shortage of the magnesium alloy to cause blockage and failure of the rotating mechanism. To avoid the foregoing problem, the aluminum alloy is directly selected in the industry as a material of the rotating open region in the middle frame. However, this reduces the lightness and thinness of the electronic device and cannot meet market requirements. To solve the foregoing problem, embodiments of this application provide a foldable structural member, and a special corrosion protection design of the foldable structural member can effectively solve a galvanic corrosion problem of the magnesium alloy in the foldable structural member.

1 FIG.A 3 FIG.D 1 FIG.C 1 FIG.A 1 FIG.B 100 30 10 20 30 100 10 20 30 100 10 20 30 Referring toto, embodiments of this application provide a foldable structural member, including a rotating mechanism, and a first middle frameand a second middle framethat are rotatably connected to the rotating mechanism. In a process of unfolding and folding the foldable structural member, the first middle frameand the second middle framerotate in a cambered dotted arrow direction inaround the rotating mechanism. When the foldable structural memberis fully unfolded, as shown inand, the first middle frameand the second middle frameare disposed on two opposite sides of the rotating mechanism, respectively.

10 11 11 111 20 21 21 211 30 111 211 The first middle frameincludes a first backplane, the first backplanehaving a first surface. The second middle frameincludes a second backplane, the second backplanehaving a second surface, and the rotating mechanismlapping over the first surfaceand the second surface.

113 213 113 111 30 213 211 30 11 30 11 111 11 11 113 21 30 21 211 21 21 113 21 100 113 213 113 213 11 21 113 213 30 113 213 11 21 100 113 213 2 FIG.A 2 FIG.B 2 FIG.B 2 FIG.B 1 2 1 2 1 2 1 2 1 2 1 2 A first regionand a second regionare defined, the first regionincluding a side border that is of the first surfaceand that is close to the rotating mechanism, and the second regionincluding a side border that is of the second surfaceand that is close to the rotating mechanism. Specifically, referring toand, on a side edge that is of the first backplaneand that is close to the rotating mechanism(for ease of description, the side edge is denoted as a first side edge of the first backplane), on the first surfaceof the first backplane, a region that faces away from the first side edge from a contour line of the first side edge and covers a first width toward a center of the first backplaneis the first region(that is, a region of the first width Win a direction of a black dotted arrow infrom the contour line of the first side edge). Correspondingly, on a side edge that is of the second backplaneand that is close to the rotating mechanism(for ease of description, the side edge is denoted as a side edge A of the second backplane), on the second surface, a region that faces away from the side edge A from a contour line of the side edge A of the second backplaneand covers a second width toward a center of the second backplaneis the second region(that is, a region of the second width Win a direction of a black dotted arrow at the second backplaneinfrom the contour line of the side edge A). Values of Wand Wmay be adapted and adjusted based on a size of the foldable structural member, for example, 0.5 mm to 2.0 mm, so that the first regionand the second regioncover at least a part of the rotating open region. Specifically, values of Wand Wmay be independently 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, or the like. In addition, the first regionand the second regionmay further continuously extend to central positions of the first backplaneand the second backplane(that is, Wand Ware increased) in a direction to which the black dotted arrow points, respectively. Alternatively, the first regionand the second regionmay be reduced toward a side of the rotating mechanism(that is, the first regionand the second regionare reduced toward the first side edge of the first backplaneand the side edge A of the second backplanein a direction that faces away from the black dotted arrow, to reduce Wand W). In the embodiments of this application, values of Wand Wmay be the same or different. It may be understood that when the foldable structural memberis completely folded, the first regionis opposite to the second region.

100 30 11 21 30 113 11 213 21 113 213 100 100 2 FIG.B Generally, in the foldable structural member, to fasten the rotating mechanism, screw holes are disposed on the first backplaneand the second backplane. The screw holes are adapted to screws. The screws are configured to fasten the rotating mechanism. In some implementations of this application, referring to, the first regionextends to a side that is of the screw hole and that faces away from the first side edge of the first backplane, and the second regionextends to a side that is of the screw hole and that faces away from the side edge A of the second backplane. In other words, the screw holes are disposed in both the first regionand the second region. In this way, a galvanic corrosion resistance effect of the rotating open region of the foldable structural membercan be further improved, and folding and unfolding of the foldable structural membercannot be affected.

3 FIG.A 3 FIG.C 11 21 40 50 40 70 50 113 213 60 70 50 40 10 20 40 50 40 40 70 113 213 100 40 60 50 70 70 50 40 100 Referring toto, the first backplaneand the second backplaneeach include a metal body, a first protective layerdisposed on a surface of the metal body, an injection molding layerdisposed on at least a surface of the first protective layerin the first regionand the second region, and an anti-corrosion layerdisposed between the injection molding layerand the first protective layer. The metal bodyprovides structural strength for the first middle frameand the second middle frame, and plays a specific protective role. When the metal bodyis applied to the electronic device, the metal body may further serve to assist a processor of the electronic device to radiate heat. The first protective layermay protect the metal body, so as to prevent the metal bodyfrom being corroded. In particular, the injection molding layerin the first regionand the second regionmay have a better sealing effect, that is, a risk of salt spray, water vapor, or the like infiltrating into the foldable structural memberis greatly reduced. Therefore, when a material of the metal bodyis a magnesium alloy, a risk of galvanic corrosion of the magnesium alloy body in the rotating open region can be sufficiently reduced. However, the anti-corrosion layermay significantly increase an interface bonding force between the first protective layerand the injection molding layer, and avoid a case that the injection molding layerand the first protective layerare poorly bonded and layered, thereby significantly reducing the risk of galvanic corrosion of the metal body, significantly improving environmental stability of the metal body, and further providing feasibility for the magnesium alloy to be used as the metal body of the rotating open region in the foldable structural member.

60 70 50 70 111 40 60 40 70 111 40 60 40 70 211 40 60 40 70 111 40 60 40 60 70 70 211 40 60 40 60 70 3 FIG.A 3 FIG.B In the embodiments of this application, that the anti-corrosion layeris disposed between the injection molding layerand the first protective layerincludes but is not limited to the following case: an orthographic projection of the injection molding layeron the first surfaceon the metal bodyfalls into an orthographic projection of the anti-corrosion layeron the metal body, and specifically, includes but is not limited to the following two cases: (1) as shown in, the orthographic projection of the injection molding layeron the first surfaceon the metal bodycompletely coincides with the orthographic projection of the anti-corrosion layeron the metal body; an orthographic projection of the injection molding layeron the second surfaceon the metal bodycompletely coincides with the orthographic projection of the anti-corrosion layeron the metal body; (2) as shown in, the orthographic projection of the injection molding layeron the first surfaceon the metal bodyfalls into the orthographic projection of the anti-corrosion layeron the metal body, and the anti-corrosion layerhas a surface that is not covered by the injection molding layer; and the orthographic projection of the injection molding layeron the second surfaceon the metal bodyfalls into the orthographic projection inside of the anti-corrosion layeron the metal body, and the anti-corrosion layerhas a surface that is not covered by the injection molding layer.

111 211 70 40 60 40 60 70 11 113 111 11 11 70 60 11 40 10 211 21 21 21 70 60 21 111 11 50 60 211 21 50 60 40 60 50 111 11 60 50 211 21 3 FIG.B 1 1 1 1 1 1 1 1 1 In some implementations of this application, on the first surfaceand/or the second surface, the orthographic projection of the injection molding layeron the metal bodyfalls into the orthographic projection of the anti-corrosion layeron the metal body(that is, a part of the surface of the anti-corrosion layeris still not covered by the injection molding layer). The following uses the first backplaneas an example for detailed description. Referring to, a width of the first regionis W, that is, on the first surface, in a direction (that is, a direction to which the black dotted arrow points) from the contour line on the first side edge of the first backplanetoward a center of the first backplane, a width of the injection molding layeris W, a width of the anti-corrosion layeris W′, and W′ is larger than W. In this way, a thickness of a central region of the first backplanecan be further reduced while an anti-corrosion requirement of the metal bodycan be met, and more accommodating space is reserved for the first middle framefor accommodating another component such as a processor, thereby reducing a total thickness of the final electronic device and further improving the lightweight degree of the electronic device. Further, a value of W′-Wmay be within a range of 0.03 mm to 20 mm. Specifically, a value of W′-Wmay be 0.03 mm, 0.05 mm, 0.10 mm, 0.20 mm, 0.50 mm, 0.80 mm, 1.00 mm, 2.00 mm, 5.00 mm, 8.00 mm, 10.00 mm, 12.00 mm, 15.00 mm, 18.00 mm, 20.00 mm, or the like. On the second surfaceof the second backplane, in a direction from the contour line on the side edge A of the second backplanetoward a center of the second backplane, the width of the injection molding layeris greater than the width of the anti-corrosion layer. Specifically, the case on the second backplanemay be adapted based on the foregoing principle, and details are not described herein again. In some specific embodiments, on the first surfaceof the first backplane, at least a part of the region of the first protective layeris not covered by the anti-corrosion layer. In addition, on the second surfaceof the second backplane, at least a part of the region of the first protective layeris not covered by the anti-corrosion layer. In this way, a total thickness of the final electronic device can be further reduced while the anti-corrosion requirement of the metal bodycan be met. The lightweight degree of the final electronic device can be further improved, and production costs can be reduced. Certainly, full coverage of the anti-corrosion layercan be implemented on the surface of the first protective layeron the first surfaceof the first backplanebased on actual application. Similarly, full coverage of the anti-corrosion layercan be implemented on the surface of the first protective layeron the second surfaceof the second backplane.

111 211 70 40 60 40 60 70 In some other implementations of this application, on the first surfaceand/or the second surface, the orthographic projection of the injection molding layeron the metal bodycompletely coincides with the orthographic projection of the anti-corrosion layeron the metal body. In this way, the anti-corrosion layeris also not disposed in a region in which the injection molding layeris not disposed, which helps to reduce production costs. It may be selected based on actual application requirements.

50 40 40 50 In the embodiments of this application, it should be further noted that the first protective layeris disposed on the surface of the metal body. Specifically, all surfaces of the metal bodyare covered by the first protective layer.

40 11 21 11 21 In some implementations of this application, the material of the metal bodyis a magnesium alloy. The magnesium alloy has a smaller density and a high specific strength. The matrix metal is made of a magnesium alloy, which may reduce weights of the first backplaneand the second backplanewhile ensuring strength of the first backplaneand the second backplane, thereby increasing the lightness and thinness of the electronic device. The magnesium alloy may be a profile magnesium alloy, may be a die cast magnesium alloy, or may be a semi-solid magnesium alloy, which is not limited thereto. In some implementations, the magnesium alloy may be a magnesium aluminum alloy, or may be a magnesium lithium alloy, but is not limited thereto. Specifically, the magnesium alloy may be selected from at least one of an AZ series magnesium alloy, an AM series magnesium alloy, an AE series magnesium alloy, and an AS series magnesium alloy.

11 112 111 114 111 112 114 60 70 50 40 1 FIG.D In some implementations of this application, the first backplanehas a third surfaceopposite to the first surfaceand a fourth surface(as shown in) that connects the first surfaceto the third surface, the fourth surfaceincluding the anti-corrosion layerand the injection molding layerthat are successively stacked on a surface that is of the first protective layerand that faces away from the metal body.

21 212 211 211 212 60 70 50 40 10 20 1 FIG.D And/or, the second backplanehas a fifth surfaceopposite to the second surfaceand a sixth surface (not shown in) that connects the second surfaceto the fifth surface, the sixth surface including the anti-corrosion layerand the injection molding layerthat are successively stacked on a surface that is of the first protective layerand that faces away from the metal body. In this way, the corrosion resistance of the first middle frameand the second middle framecan be comprehensively improved, so that the final foldable electronic device passes a complete-machine salt spray test.

11 11 114 100 114 50 114 60 70 The following uses the first backplaneas an example for detailed description. One end of the first side edge of the first backplaneis sequentially connected to a second side edge, a third side edge, and a fourth side edge, where the fourth side edge is connected to the other end of the first side edge. Surfaces of the first side edge, the second side edge, the third side edge, and the fourth side edge jointly constitute the fourth surface. It may be understood that, to adequately ensure an anti-corrosion effect of the foldable structural member, the fourth surfacealso needs to perform anti-corrosion processing. Therefore, the surface of the first protective layerof the fourth surfacefurther includes the anti-corrosion layerand the injection molding layerthat are successively stacked. Similarly, the second backplane also includes four side edges, and surfaces of the four side edges jointly constitute the sixth surface. A specific case may be adapted based on the foregoing principle, and details are not described herein again.

114 11 40 60 70 114 111 11 60 70 114 111 111 70 70 113 70 70 113 60 60 113 40 60 70 21 In some specific implementations, the fourth surfaceof the first backplanedoes not expose the metal body. In some specific embodiments, further, the anti-corrosion layerand the injection molding layermay further extend from the fourth surfaceto the first surfaceof the first backplane. A case of the second side edge is used as an example. The anti-corrosion layerand the injection molding layerextend from the fourth surfaceto an edge region that is of the first surfaceand that is close to the second side edge, and a width dimension of the region on the first surfacemay be determined based on an actual application requirement. It should be noted that the injection molding layeron the first side edge is connected to the injection molding layeron the first region, so as to improve the anti-corrosion effect. Further, the injection molding layeron the first side edge is seamlessly connected to the injection molding layeron the first region. The anti-corrosion layeron the first side edge is seamlessly connected to the anti-corrosion layeron the first region. Similarly, the sixth surface of the second backplane does not expose the metal body, and a case in which the anti-corrosion layerand the injection molding layerof the second backplanemay be adapted based on the foregoing principle. Details are not described herein again.

70 70 100 70 In some implementations of this application, a thickness of the injection molding layeris within a range of 0.15 mm to 0.35 mm. In this way, the protective performance of the injection molding layerand the lightness and thinness of the foldable structural membercan be both considered. Specifically, the thickness of the injection molding layermay be 0.15 mm, 0.18 mm, 0.20 mm, 0.22 mm, 0.25 mm, 0.28 mm, 0.30 mm, 0.32 mm, 0.35 mm, or the like.

1 FIG.B 1 FIG.C 4 FIG.A 10 12 11 20 22 21 12 11 21 22 12 22 12 22 111 11 111 22 211 21 211 12 22 12 22 Referring totoand, in some implementations of this application, the first middle framefurther includes a first side framefastened to the first backplane. The second middle framefurther includes a second side framefastened to the second backplane. The first side frame, the first backplane, the second backplane, and the second side frameconstitute a first accommodating space. The first side frameand the second side frameare manufactured by injection molding. The first side frameand the second side frameextend toward the first surfaceof the first backplane, and extension directions thereof are perpendicular to the first surface. The second side frameextends toward the second surfaceof the second backplane, and an extension direction thereof is perpendicular to the second surface. The first side frameand the second side framehave limiting and protecting effects on an outer side border of the display of the electronic device. Specifically, the first accommodating space may be the same as accommodating components such as a first display module and a heat dissipation plate. The first display module includes a first display, and the first display is a flexible screen. In addition, the first side frameand the second side framefurther participate in constituting an appearance surface of the foldable electronic device.

4 FIG.B 4 FIG.C 12 112 11 112 22 212 21 212 12 11 22 21 100 112 11 212 21 60 70 112 11 60 70 212 20 In some implementations of this application, referring to, the first side framefurther extends toward the third surfaceof the first backplane, and the extension direction thereof is further perpendicular to the third surface. The second side framefurther extends toward the fifth surfaceof the second backplane, and the extension direction thereof is further perpendicular to the fifth surface. In this way, the first side frame, the first backplane, the second side frame, and the second backplanefurther constitute a second accommodating space, and the second accommodating space may be used to accommodate a battery component and the like. When the foldable structural memberis fully unfolded, the second accommodating space and the first accommodating space are disposed oppositely. In some specific implementations, a second display module is disposed in the second accommodating space. In this case, the second display module is located on the third surfaceof the first backplane, or is located on the fifth surfaceof the second backplane. Further, referring to, the anti-corrosion layerand the injection molding layerfurther extend to the third surfaceof the first backplane, and/or the anti-corrosion layerand the injection molding layerfurther extend to the fifth surfaceof the second backplane. Further, the second middle framemay be adapted based on the foregoing principle, and details are not described herein again.

12 70 11 22 70 21 10 20 70 60 11 21 12 11 22 21 12 70 22 70 In some implementations of this application, the first side frameis integrally molded with the injection molding layeron the first backplane, and the second side frameis integrally molded with the injection molding layeron the second backplane. In this way, structural strength of the first middle frameand the second middle frameis further improved. In this case, it may be understood that, a side surface that is of the injection molding layerand that is close to the anti-corrosion layeris a flat surface attached to the first backplaneand the second backplane, and the first side frameprotrudes relative to the first backplane, thereby implementing a limiting effect on the display. Similarly, the second side frameprotrudes relative to the second backplane. The first side frameis seamlessly connected to the injection molding layer, and the second side frameis seamlessly connected to the injection molding layer.

70 70 70 70 70 70 70 In some implementations, a material of the injection molding layeris an inorganic material reinforced resin. In some implementations of this application, the material of the injection molding layeris an inorganic fiber reinforced resin. An inorganic fiber includes but is not limited to a glass fiber (GF). The resin includes but is not limited to at least one of a polycarbonate (PC), a polybutylene terephthalate (PBT), a polyphenylene sulfide (PPS), and a polyamide (PA). That is, the material of the injection molding layermay be at least one of a GF-enhanced PC, a GF-enhanced PBT, a GF-enhanced PPS, and a GF-enhanced PA, but is not limited thereto. In this way, corrosion resistance and strength of the injection molding layermay be considered. In some specific embodiments, weight percentage content of the inorganic fiber in the injection molding layeris 10%-60%. Specifically, the weight percentage content of the inorganic fiber in the injection molding layermay be 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%, or the like. In this way, the injection molding layermay have better toughness, better compactness, and higher strength.

12 22 12 22 100 12 22 12 22 In some implementations of this application, a material of the first side frameand a material of the second frameare inorganic material reinforced resins. In this case, the first side frameand the second framehave better strength, excellent anti-fall performance, and excellent sealing and corrosion resistance. In addition, when the foldable structural memberis used for the electronic device, an antenna module of the electronic device may transmit an electrical signal to the outside by using the first side frameand the second side frame, and receive the external electrical signal, so as to implement a communication function of the electronic device. In addition, in this case, a non conductive vacuum metalization (NCVM) system appearance may further be formed on outer surfaces of the first side frameand the second side frame, so as to improve the appearance of the final foldable electronic device.

12 22 12 22 70 12 22 12 22 70 In some implementations of this application, the material of the first side frameand the material of the second side frameare independently selected from at least one of a GF-enhanced PC, a GF-enhanced PBT, a GF-enhanced PPS, and a GF-enhanced PA, which is not limited thereto. In some specific embodiments, the material of the first side frameand the material of the second side frameare the same as the material of the injection molding layer. In this case, weight percentage content of the inorganic fiber in the first side frameand weight percentage content of the inorganic fiber in the second side framemay be the same or different. The weight percentage content of the inorganic fiber in the first side frameand the weight percentage content of the inorganic fiber in the second side framemay be the same as or different from weight percentage content of the inorganic fiber in the injection molding layer.

50 40 50 50 In some implementations of this application, the first protective layeris a ceramic layer formed by micro-arc oxidation. The micro-arc oxidation may grow a uniform ceramic layer on the surface of the metal bodyin situ, and the formed ceramic layer has high hardness, high corrosion resistance, and good insulation performance. In some implementations of this application, resistance of the first protective layeris greater than or equal to 3 MΩ. In some implementations of this application, the material of the first protective layerincludes but is not limited to at least one of magnesium silicate, magnesium oxide, magnesium hydroxide, and magnesium chloride.

50 50 50 50 60 50 60 60 50 50 50 50 40 50 40 In some implementations of this application, the first protective layerhas a porous structure, the first protective layerhas a porosity of less than or equal to 15%, and the porous structure has an aperture of less than or equal to 20 μm. That is, in some specific implementations, the ceramic layer formed by the micro-arc oxidation has a porosity of less than or equal to 15%, and the porous structure has an aperture of less than or equal to 20 μm. Specifically, the porosity may be but is not limited to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or the like. Specifically, the aperture of the porous structure may be but is not limited to 0.5 μm, 1.0 μm, 2.0 μm, 3.0 μm, 4.0 μm, 5.0 μm, 6.0 μm, 6.5 μm, 7.0 μm, 8.0 μm, 9.0 μm, 10.0 μm, 11.0 μm, 12.0 μm, 13.0 μm, 14.0 μm, 15.0 μm, 16.0 μm, 17.0 μm, 18.0 μm, 19.0 μm, 20.0 μm, or the like. In some specific implementations, apertures of a plurality of holes in the first protective layerare distributed within a range of 0.5 μm to 20 μm. Further, the apertures may be distributed within a range of 6.6 μm to 20 μm. In this way, on one hand, the first protective layerhas a certain amount of pores having relatively large apertures, which can significantly increase an interface bonding force between the anti-corrosion layerand the first protective layer. Especially, when the anti-corrosion layeris a resin layer, in a preparation process, materials of the resin layer may flow into the pores (more easily flows into pores with larger apertures, pores having apertures greater than 5 μm). After curing, the bonding force between the anti-corrosion layerand the first protective layeris significantly increased, and the pores can be sealed. On the other hand, small holes having smaller apertures (pores having apertures of less than or equal to 5 μm) are distributed in the first protective layer, and an entire porosity of the first protective layermay be adjusted to be within a proper range, so that the first protective layerfurther has specific compactness. In addition, salt spray and water vapor are not prone to infiltrate into the pores having smaller apertures, so that a risk that fine droplets such as salt spray infiltrating into the surface of the metal bodythrough the first protective layercan be further reduced, and when the material of the metal bodyis a magnesium alloy, galvanic corrosion can be further reduced, and environmental stability of the final foldable electronic device can be improved.

50 50 50 60 In some implementations of this application, surface roughness of the first protective layeris greater than or equal to 32 A. For example, the surface roughness of the first protective layeris 32 A-50 A. In this way, the interface bonding force between the first protective layerand the anti-corrosion layeris increased, and the galvanic corrosion in the rotating open region is further reduced.

50 50 50 10 20 50 50 50 50 50 50 50 50 50 50 In some implementations of this application, a thickness of the first protective layeris within a range of 15 μm to 40 μm. In this way, protective performance of the first protective layercan be further improved, salt spray and water vapor are further prevented from penetrating through the first protective layer, and a total thickness of the first middle frameand the second middle framecan be ensured to be smaller, thereby considering the lightness and thinness of the final electronic device. It may be understood that, when the first protective layerhas a porous structure, the pores of the first protective layerare randomly arranged (pore structures are intersected and distributed in the first protective layer, and the pores on the surface of the first protective layerare in typical volcanic hole shapes). When the thickness of the first protective layeris within a proper range, a path that fine droplets such as salt spray need to go when penetrating through the first protective layercan be significantly increased, and more obstacles are also disposed, thereby improving the protective effect. Specifically, the thickness of the first protective layermay be 15 μm, 15.5 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 28 μm, 30 μm, 32 μm, 34 μm, 35 μm, 36 μm, 38 μm, 39 μm, or the like. In some specific embodiments of this application, the first protective layerhas a porous structure, the first protective layerhas a porosity of less than or equal to 15%, the porous structure has an aperture of less than or equal to 20 μm, and the thickness of the first protective layeris within a range of 15 μm to 40 μm.

60 In the embodiments of this application, the anti-corrosion layermay be a single-layer structure, a double-layer structure, or a three-layer structure, which is not limited thereto.

60 60 50 50 60 50 60 50 70 60 70 60 50 70 40 60 60 60 In some implementations of this application, the anti-corrosion layeris a resin layer (that is, the anti-corrosion layeris a single-layer structure). The material of the resin layer includes a cured product of an epoxy resin, a polyester resin and a silane coupling agent. In this way, in the preparation process, a mixture of an epoxy resin, a polyester resin, and a silane coupling agent may be coated on the surface of the first protective layer, and the mixture may be immersed in some pores of the first protective layer. In addition, the epoxy resin and the polyester resin have a higher Van der Waals force. After the mixture is cured, the materials of the anti-corrosion layer(that is, the resin layer) are further dispersed in the first protective layer, so as to increase the interface bonding force between the anti-corrosion layerand the first protective layer. In addition, when the material of the injection molding layerincludes the inorganic material reinforced resin, the interface bonding force between the resin in the anti-corrosion layerand the resin in the injection molding layeris good. Therefore, the anti-corrosion layermay serve to bridge the first protective layerand the injection molding layer, and a firm anti-corrosion and water-proof structure is formed on a surface of a corresponding region of the metal body, thereby greatly reducing a risk of galvanic corrosion of a magnesium alloy body, and ensuring that the final electronic device meets requirement for the whole-machine salt spray test. In addition, the cured product of an epoxy resin, a polyester resin and a silane coupling agent has better water-boiling, high-temperature, and high-humidity resistance properties. In this case, in some implementations of this application, a thickness of the anti-corrosion layeris within a range of 10 μm to 40 μm. Specifically, the thickness of the anti-corrosion layermay be but is not limited to 10 μm, 12 μm, 15 μm, 20 μm, 22 μm, 24 μm, 25 μm, 28 μm, 30 μm, 32 μm, 35 μm, 38 μm, 40 μm, or the like. The thickness of the anti-corrosion layeris controlled to be within the foregoing range, and better corrosion resistance and a higher degree of lightness and thinness can be considered.

60 60 60 In some specific embodiments of this application, a first-type inorganic filler is further distributed in the resin layer, where the first-type inorganic filler includes but is not limited to at least one of a hydrophobic silicon dioxide, talc, and magnesium powder. The first-type inorganic filler may increase coverage of the resin layer in the preparation process of the resin layer, that is, reduce particles caused by ambient dust in a spraying process, thereby increasing flatness of the resin layer (that is, the anti-corrosion layer), and improving corrosion resistance of the resin layer (that is, the anti-corrosion layer). In addition, the first-type inorganic filler may further form a hydrophobic nanostructure of the anti-corrosion layer, thereby improving corrosion resistance of the first-type inorganic filler.

60 60 50 50 70 60 50 70 60 3 FIG.A 3 FIG.B In some implementations of this application, the anti-corrosion layerincludes a first resin layer and a second resin layer that are stacked (the anti-corrosion layeris a double-layer structure, which is not shown into), and the first resin layer is in contact with the first protective layer. The first resin layer includes a material prepared from an epoxy resin, a polyester resin, and a silane coupling agent. The second resin layer includes a cured product of a first-type acrylic resin and an isocyanate. Hydroxyl molar content of the first-type acrylic resin is greater than or equal to 1.0%. Similarly, the first resin layer may partially infiltrate into voids in the first protective layer, so as to implement better bonding force. However, the second resin layer and the injection molding layermay implement better interface bonding force. Therefore, the anti-corrosion layermay cooperate with the first protective layerand the injection molding layerto form a firm anti-corrosion barrier. In this case, a thickness of the first resin layer is within a range of 2 μm to 10 μm, and a thickness of the second resin layer is within a range of 10 μm to 30 μm. Specifically, in the anti-corrosion layerof the double-layer structure, the thickness of the first resin layer may be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or the like. Specifically, content of the second resin layer may be 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, or the like.

60 60 60 60 In some specific embodiments of this application, the first-type inorganic filler is further distributed in the first resin layer. A second-type inorganic filler is further distributed in the second resin layer. The first-type inorganic filler includes but is not limited to at least one of hydrophobic silicon dioxide, talc powder, and magnesium powder. The second-type inorganic filler includes but is not limited to at least one of silicon dioxide, barium sulfate, and titanium dioxide. That is, the first resin layer includes a resin distributed with the first-type inorganic filler, and the resin includes the material prepared from an epoxy resin, a polyester resin, and a silane coupling agent. The second resin layer includes a cured product of a first-type acrylic resin distributed with the second-type inorganic filler and an isocyanate. Similarly, the first-type inorganic filler may increase coverage of the resin layer in the preparation process of the resin layer, that is, reduce particles caused by ambient dust in a spraying process, thereby increasing flatness of the resin layer (that is, the anti-corrosion layer), and improving corrosion resistance of the resin layer (that is, the anti-corrosion layer). In addition, the first-type inorganic filler may further form a hydrophobic nanostructure of the anti-corrosion layer, thereby improving corrosion resistance of the first-type inorganic filler. The second-type inorganic filler may increase a surface dyne value of the second resin layer, thereby increasing an adhesive force between the injection molding layer and the anti-corrosion layer, and facilitating the corrosion resistance of the final electronic device.

60 60 50 60 60 60 3 FIG.A 3 FIG.B In some other implementations of this application, a transition layer is further disposed between the first resin layer and the second resin layer (the anti-corrosion layeris a three-layer structure, which is not shown into). That is, the anti-corrosion layerincludes a first resin layer, a transition layer, and a second resin layer that are successively stacked, and the first resin layer is in contact with the first protective layer. In this case, the transition layer includes a second-type hydroxyacrylic resin. Molar content of a hydroxyl group in the second-type acrylic resin is less than or equal to 1.0%. The transition layer serves to connect the first resin layer to the second resin layer, and further improves stability of the anti-corrosion layerof a three-layer structure. In the three-layer structure, the thickness of the first resin layer is within a range of 2 μm to 10 μm. The thickness of the second resin layer is within a range of 2 μm to 10 μm. A thickness of the transition layer is within a range of 10 μm to 20 μm. Specifically, in the anti-corrosion layerof a three-layer structure, the thickness of the first resin layer and the thickness of the second resin layer may be independently 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or the like. Specifically, in the anti-corrosion layerof a three-layer structure, the thickness of the transition layer may be 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, or the like.

60 In the embodiments of this application, the anti-corrosion layermay be prepared by using electrophoresis, or may be prepared by using a coating process.

60 50 60 50 In the embodiments of this application, an adhesive force between the anti-corrosion layerand the first protective layeris greater than or equal to 4B. In the embodiments of this application, a water-boiling adhesive force between the anti-corrosion layerand the first protective layeris greater than or equal to 4B.

40 50 60 60 70 60 70 60 60 70 80 111 11 111 11 80 60 70 70 211 21 80 60 70 70 80 60 60 3 FIG.C An injection molding process is to place the metal bodyprovided with the first protective layerand the anti-corrosion layerin corresponding regions in an injection molding cavity, and perform injection molding processing on a specified region in a high-temperature and high-pressure environment. In some cases, cracks occur in the anti-corrosion layerin a region adjacent to the injection molding layer, and corrosion resistance of the anti-corrosion layeris affected. In other words, when the injection molding layerdoes not cover all surfaces of the anti-corrosion layer, cracks may occur on a surface that is of the anti-corrosion layerand that is adjacent to an edge of the injection molding layer. In some implementations of this application, referring to, a second protective layeris further disposed on the first surfaceof the first backplane. Specifically, on the first surfaceof the first backplane, the second protective layeris further disposed in at least a part of a region that is on a surface on which the anti-corrosion layeris not covered by the injection molding layerand that is adjacent to the injection molding layer. Similarly, on the second surfaceof the second backplane, the second protective layeris further disposed in at least a part of a region that is on a surface on which the anti-corrosion layeris not covered by the injection molding layerand that is adjacent to the injection molding layer. In this way, the second protective layermay seal a gap that appears on an exposed surface of the anti-corrosion layercaused by injection molding, so as to prevent the salt spray water vapor from infiltrating into the anti-corrosion layerthrough the gap, thereby greatly reducing a galvanic corrosion speed, and the final electronic device meets the requirements for the whole-machine salt spray test.

80 70 In some implementations of this application, the second protective layeris connected to the injection molding layer.

3 FIG.D 80 70 60 80 60 70 60 60 80 70 60 In some implementations of this application, referring to, the second protective layerfurther covers a surface that is of the injection molding layerand that faces away from the anti-corrosion layer. It may be understood that, in this case, the second protective layermay better cover the exposed surface of the anti-corrosion layerat an interface between the injection molding layerand the anti-corrosion layer, so as to better prevent salt spray and water vapor from infiltrating into the anti-corrosion layerthrough the gap. Further, in some specific embodiments, the second protective layermay further cover a surface that is of the injection molding layerand that faces away from the anti-corrosion layer.

80 80 80 11 21 11 21 80 In some implementations of this application, a thickness of the second protective layeris within a range of 5 μm to 30 μm. Specifically, the thickness of the second protective layerrefers to a maximum size of a cross section of the second protective layer, and the cross section refers to a surface obtained by cutting the first backplane(or the second backplane) by using a plane perpendicular to a thickness direction of the first backplane(or the second backplane). Specifically, the thickness of the second protective layermay be 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, 32 μm, 35 μm, 38 μm, 40 μm, or the like. In this way, the lightness and thinness of the final electronic product can be improved while the anti-corrosion effect is fully improved.

80 In some implementations of this application, the second protective layerincludes a fluorine-containing resin. The fluorine-containing resin not only has better compactness, but also has specific hydrophobicity, which further improves waterproof performance and corrosion resistance. Specifically, the fluorine-containing resin includes but is not limited to at least one of a fluoroacrylate, a fluorosilyl acrylate, a fluorocarbamate, a perfluoropolyether, a perfluoropolyoxane, a fluoropolymer, a polytetrafluoroethylene, a polyvinylidene fluoride, a fluorosiloxane, 1,1,1,2,3,4,5,5,5-monofluoro-4-methoxypentan-2-ene, and a perfluorohexanol tridecafluorooctanol.

80 60 70 80 60 In some other implementations of this application, the second protective layerincludes a cured product of a third-type hydroxyacrylic resin and an isocyanate. Molar content of a hydroxyl group in the third-type hydroxyacrylic resin is greater than or equal to 1.0 (a hydroxyl value is greater than or equal to 33), so as to increase a crosslinking degree of a high molecular chain in the second protective layer, to form a dense macromolecular mesh structure, thereby improving the corrosion resistance. In this case, the second protective layer also has better compactness, and a bonding property between the material of the anti-corrosion layerand the material of the injection molding layeris better. In some implementations of this application, the third-type hydroxyacrylic resin is the same as the first-type hydroxyacrylic resin. Further, the material of the second protective layeris the same as that of the second resin layer in the anti-corrosion layer.

30 In some implementations of this application, the rotating mechanismincludes but is not limited to a hinge.

100 1 S: Provide a metal body, and form a first protective layer on a surface of the metal body. 2 S: Form an anti-corrosion layer on at least a surface of a first protective layer in a first region and a second region. 3 70 S: Form the injection molding layeron at least a surface of the anti-corrosion layer in the first region and the second region, to manufacture the foldable structural member. Correspondingly, the embodiments of this application further provide a manufacturing method of the foldable structural member, including:

1 In some implementations of this application, before step S, the method further includes preprocessing the metal body. It may be understood that when a material of the metal body is a magnesium alloy, corrosion resistance of the magnesium alloy is poor, and therefore, a manufacturer may form a coating (for example, a phosphating layer of the magnesium alloy) on a surface of a magnesium alloy original material. Therefore, preprocessing of the magnesium alloy includes sequentially performing degreasing, washing, peeling, washing, neutralizing, and washing.

1 In step S, a micro-arc oxidation process is used to form a first protective layer on a surface of the metal body obtained by preprocessing. Specifically, the pre-processed metal body is placed in an electrolyte immersed in an electrolytic cell. The metal body is used as an anode, and the electrolytic cell is used as a cathode. An electric field is applied to perform micro-arc oxidation, so that a surface layer of the metal body is melted, and a ceramic layer with high hardness, good corrosion resistance, and good electrical insulation performance is formed on the surface of the metal body after an obtained melt is in contact with the electrolyte. In some implementations, the electrolyte includes a solvent, a salt, and a nano additive, where the salt includes but is not limited to at least one of a silicate, a phosphate, and an aluminate. In some implementations, the micro-arc oxidation is performed on the metal body at a current density of 1 A to 5 A. Specifically, the current density may be 1.5 A, 2.0 A, 2.2 A, 2.4 A, 2.5 A, 3.0 A, 3.5 A, 4.0 A, 4.2 A, 4.5 A, 4.8 A, 5.0 A, or the like. In some specific embodiments, the metal body is immersed in the electrolyte containing a salt and a nano additive, and the micro-arc oxidation is performed on the metal body by using a current density of 2 A to 5 A. In this way, a first protective layer with a thickness of 15 μm to 40 μm may be formed on the surface of the metal body.

1 In some implementations of this application, in step S, voltage of the electric field does not exceed 1000 V.

1 In some implementations of this application, in step S, a duty ratio of the micro-arc oxidation process is within a range of 5%-25%. The duty ratio is a ratio of power-on time to total time in a pulse cycle of the micro-arc oxidation. Specifically, the duty ratio of the micro-arc oxidation process may be 5%, 6%, 10%, 15%, 20%, 22%, 25%, or the like.

1 In some implementations of this application, in step S, a temperature of the electrolyte is within a range of 15° C.-25° C. Specifically, the temperature of the electrolyte may be 15° C., 18° C., 20° C., 22° C., 25° C., or the like.

1 In some implementations of this application, in step S, a pulse frequency used for the micro-arc oxidation is 800 Hz to 1000 Hz. Specifically, the pulse frequency used for the micro-arc oxidation may be 800 Hz, 850 Hz, 900 Hz, 950 Hz, 980 Hz, or the like.

1 In some implementations of this application, in step S, a duration of performing the micro-arc oxidation process is 20 min to 40 min. Specifically, the duration of performing the micro-arc oxidation process may be 20 min, 25 min, 30 min, 35 min, 40 min, or the like.

2 In some implementations of this application, in step S, the anti-corrosion layer may be manufactured by using an electrophoretic process, and may alternatively be manufactured by using a coating process.

2 In some implementations of this application, when the anti-corrosion layer is a single-layer structure (the anti-corrosion layer is a resin layer), a first mixture is coated on at least the surface of the first protective layer in the first region and the second region, where the first mixture includes an epoxy resin, a polyester resin, and a silane coupling agent, and is placed at 80° C.-120° C. to bake for 15 min to 30 min to obtain a cured product of an epoxy resin, a polyester resin, and a silane coupling agent, so as to obtain the anti-corrosion layer. In some specific embodiments of this application, step Sfurther includes adding the first-type inorganic filler to the first mixture.

2 In some implementations of this application, when the anti-corrosion layer is a double-layer structure, the first mixture is coated on at least the surface of the first protective layer in the first region and the second region, and is placed at 80° C.-120° C. to bake for 15-30 min to obtain a first resin layer, and a second mixture is coated on a surface of the first resin layer. The second mixture includes a cured product of a first-type hydroxyacrylic resin and an isocyanate, and is baked at 80° C.-120° C. for 30 min to 40 min, so that the cured product of a first-type hydroxyacrylic resin and an isocyanate reacts to obtain a second resin layer, so as to obtain an anti-corrosion layer with a double-layer structure. In some specific embodiments of this application, step Sfurther includes adding a first-type inorganic filler to the first mixture; and adding a second-type inorganic filler to the second mixture, where the second-type inorganic filler includes but is not limited to at least one of gas-phase silicon dioxide, barium sulfate, and titanium dioxide.

In some implementations of this application, when the anti-corrosion layer is a three-layer structure, the first mixture is coated on at least the surface of the first protective layer in the first region and the second region, and is placed at 80° C.-120° C. to bake for 15-30 min to obtain a first resin layer, and a transition layer mixture is coated on a surface of the first resin layer. The transition layer mixture includes a second-type hydroxyacrylic resin, and is placed at 80° C.-120° C. to bake for 15 min to 30 min to obtain a transition layer. Then, the second mixture is coated on the surface of the transition layer, and is placed at 80° C.-120° C. to bake for 30 min to 40 min to obtain a second resin layer, so as to obtain an anti-corrosion layer with a three-layer structure.

2 2 In some implementations of this application, step Sfurther includes forming an anti-corrosion layer in another region on the surface of the first protective layer, so that on the first surface of the first backplane, an orthographic projection of the injection molding layer on the metal body falls into an orthographic projection of the anti-corrosion layer on the metal body, and the anti-corrosion layer has a region not covered by the injection molding layer. In some implementations of this application, step Sfurther includes forming an anti-corrosion layer in another region on the surface of the first protective layer, so that on the second surface of the second backplane, an orthographic projection of the injection molding layer on the metal body falls into an orthographic projection of the anti-corrosion layer on the metal body, and the anti-corrosion layer has a region not covered by the injection molding layer.

2 In some implementations of this application, step Sfurther includes forming an anti-corrosion layer on a sidewall of the metal body (that is, a fourth surface of the first backplane and a sixth surface of the second backplane). Further, the anti-corrosion layer on the first sidewall is further extended to an edge of the first surface of the first backplane. It should be noted that the edge of the first surface herein does not include the first region. Similarly, the second backplane may be adapted based on the foregoing situation.

3 2 3 In some implementations of this application, in step S, forming the injection molding layer on at least a surface of the anti-corrosion layer in the first region and the second region includes: placing the metal body obtained in step Sinto a cavity of the injection molding device, performing injection molding at a mold temperature of 90° C.-120° C. by using an injection molding pressure of 200 MPa, and controlling a temperature of an injection molding raw material to be 290° C.-320° C., so as to form the injection molding layer on the surface of the anti-corrosion layer in the first region and the second region. The injection molding raw material includes but is not limited to inorganic fiber reinforced resin particles. In some implementations of this application, step Sfurther includes forming the injection molding layer on the surface of the anti-corrosion layer on the sidewall of the metal body (that is, a fourth surface of the first backplane and a sixth surface of the second backplane). The first backplane is used as an example, and the injection molding layer is formed on the anti-corrosion layer on the fourth surface of the first backplane. Further, the injection molding layer on the fourth surface is further extended to the edge of the first surface of the first backplane. It should be noted that the edge of the first surface herein does not include the first region. Similarly, the injection molding layer on the sixth surface is further extended to an edge of the second surface of the second backplane. It should be noted that the edge of the second surface herein does not include the second region.

3 In some implementations of this application, step Sfurther includes forming a first side frame and a second side frame. In some specific implementations, the first side frame is integrally molded with the injection molding layer, and the second side frame is integrally molded with the injection molding layer, so that the first side frame is seamlessly connected to the injection molding layer, and the second side frame is seamlessly connected to the injection molding layer. In this way, overall structural strength of the first middle frame and the second middle frame is improved.

3 4 In some implementations of this application, after step S, the method further includes step S: forming a second protective layer in at least a part of a region that is on a surface on which the anti-corrosion layer is not covered by the injection molding layer and that is adjacent to the injection molding layer. Further, the second protective layer is connected to the injection molding layer. Further, the second protective layer is further extended to a surface that is of the injection molding layer and that faces away from the anti-corrosion layer.

4 In some implementations of this application, in step S, a process of forming the second protective layer includes: coating a fluorine-containing resin to a specified region, baking for 20 min to 50 min at 40° C. to 60° C. to obtain the second protective layer; alternatively, coating a fluorine-containing resin in a specified region, and placing at room temperature for more than 24 hours to obtain the second protective layer.

4 In some other implementations of this application, in step S, a process of forming the second protective layer includes: coating a third-type hydroxy acrylic resin and an isocyanate in a specified region, baking for 15 min to 30 min at 80° C. to 120° C. to obtain the second protective layer.

The manufacturing method has simple steps and high process reliability, and is applicable to large-scale industrial production.

The embodiments of this application further provide a foldable electronic device, including the foldable structural member provided in the embodiments of this application.

In some implementations of this application, the foldable electronic device includes but is not limited to a wearable electronic device such as a mobile phone, a notebook computer, a tablet computer, and an electronic watch.

In some implementations of this application, the foldable electronic device is a mobile phone.

In some implementations of this application, the foldable electronic device includes a first display and a second display. The first display is disposed on both a first surface of the first middle frame and a second surface of the second middle frame. The first display is a flexible display. The second display is disposed on a surface that is of the first middle frame and that faces away from the first display (that is, the third surface), or the second display is disposed on a surface that is of the second middle frame and that faces away from the first display (that is, the fifth surface). In this case, the first display may be folded and unfolded as the electronic device is folded and unfolded. It may be understood that a display backplane is further disposed on a surface that is of the first display and that faces the first middle frame and the second middle frame.

In some implementations of this application, the second display is disposed on a surface that is of the first middle frame and that faces away from the first display (that is, the third surface). In this case, a battery is disposed on a surface that is of the second middle frame and that faces away from the first display (that is, the fifth surface). In some other implementations, the second display is disposed on a surface that is of the second middle frame and that faces away from the first display (that is, the fifth surface). In this case, a battery is disposed on a surface that is of the first middle frame and that faces away from the first display (that is, the third surface).

The foregoing descriptions are merely specific implementations of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.